howtosupplement
Deficiency/Longevity/Heart

Vitamin K

Fat-soluble vitamin that supports normal clotting and may help bone and vascular health in adults with low intake.

Vitamin K

Vitamin K

72
score
B
evidence
Caution
risk
Quick Take

Useful if you eat few leafy greens or pair it with vitamin D3; do not self-start if you use warfarin.

Vitamin K is a fat-soluble vitamin found mainly as K1 in leafy greens and as K2 in natto, some cheeses, and egg yolks. It activates proteins involved in blood clotting, bone mineralization, and control of calcium in soft tissues. The best-supported uses are correcting low vitamin K status, supporting bone density, and possibly improving vascular aging markers. Adults with low vegetable intake, low-K2 diets, or long-term vitamin D3 use tend to benefit most.

Proven Benefits

01
Corrects low vitamin K status
02
Supports bone density
03
May reduce arterial stiffness
04
May reduce fracture risk
05
May slow vascular calcification
06
May improve insulin sensitivity
07
May lower hs-CRP / IL-6

Protocol

Amount
90-180 mcg
Frequency
Once daily
When
With a meal containing fat to improve absorption.

Onset Time

Days to weeks if deficient; 8-12 weeks for bone or vascular biomarkers.

Who Should Consider

Adults who rarely eat leafy greens
Adults 50+ with low fermented-food intake
People taking vitamin D3 long term
People using orlistat or bile-acid binders
Adults with low dietary variety

Food Sources

  • Natto (~400-800 mcg K2 per 40 g)
  • Kale (~500 mcg K1 per 1 cup cooked)
  • Spinach (~145 mcg K1 per 1 cup raw)
  • Broccoli (~110 mcg K1 per 1 cup cooked)
  • Hard cheeses (~10-25 mcg K2 per 30 g)
  • Egg yolk (~5-10 mcg K2 per yolk)

How It Works

Vitamin K acts as a cofactor for gamma-glutamyl carboxylase, which activates clotting factors plus osteocalcin and matrix Gla protein. This helps the body form normal clots, bind calcium into bone, and limit calcium deposition in soft tissues and arteries.

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